Cleaning and sterilizing method and apparatus



Oct. 12, 1937. H. L. JOHNSTON 2,095,502

CLEANING AND STERILIZING METHOD AND APPARATUS Filed March '6, 1931 5 Sheets-Sheet 1 INVENTOR ATTORNEY Oct. 12, 1937. H. L. JOHrQSTON 2,0 5,502

CLEANING AND STERILIZING METHOD AND APPARATUS Filed March 6, 1931 3 Sheets-Sheet 2 INVENTOR f BY JW .I WP- h pL' i 9 A ATTORNEY Oct. 12, 1937. H. L. JOHNSTON CLEANING AND S TERILIZING METHOD AND APPARATUS Fil ed March 6, 1931 s Sheets-Sheet 5 Patented Oct. 12, i931 v 2,095,502

UNITED, STATES PATENT OFFICE CLEANING AND STERILIZING METHOD AND APPARATUS Herbert L. Johnston, Troy, Ohio, minor to The Hobart Manufacturing Company, Troy, Ohio, a corporation of Ohio Application March a, 1931, Serial No. 520,594 9 Claims. (01. 21-54) This invention relates to the cleaning and Fig. 6 is a sectional view taken on the line -8 sterilizing oi dishes and like articles. oi Fig. 2;

One of the principal objects oi the invention Fig. 7 is a. diagrammatic showing oi the elecis the provision of a method oi and apparatus trical circuits oi the apparatus; and for rendering dishes, tableware and like articles Fig. 8 is a sectional view oi a sterilizer showsterile by exposing them in an eiiective manner ing a somewhat diflferent arrangement oi parts. to sterilizing light rays or radiations. The drawings, in which like characters oi rei- Another object of the invention is the proerence designate like parts throughout the sevvision oi a sterilizer through which articles are eral views thereoi, illustrate a-sterilizer which 10 adapted to be passed, and in which a sterilizing is adapted for sterilizing dishes and tableware. l0 radiation is provided that is limited to the con- The sterilizer is particularly useiul for restaufines oi the sterilizer housing; and in which conrants, soda fountains, and like places, and in hostrols are incorporated to safeguard the user oi pitals caring ior contagious patients, and serves the sterilizer and insure sterilizing action during as a simple and effective means of rendering the passage of articles therethrough. articles passed through it sterile so that they Still another object oi the invention is to promay be safely used again without risk oi spreadvide a sterilizer of this character in which pasing disease germs with which the-articles may sage oi. articles through the apparatus is autohave become contaminated during a previous matically interrupted upon failure of the sterilizuse. As shown, the sterilizer is associated with a ing rays, and in which operation oi the sterilizdishwashing mechanism so that the dishes after ing rays is automatically terminated upon the passing irom the washing machine are moved as occurrence of abnormal operating conditions. a continuous operation through the sterilizer Another object of the invention is to provide wherethey are subjected to a sterilizing radiasterllizing apparatus of this character in which tion and may also be subjected to a drying action. apparatus ior conveying the dishes or articles Although the sterilizer oi Figs. 1 and 2 is shown 2 through the sterilizer is constructed to secure transporting tumblers it is to be understood that complete and eilective exposure of the articles to the device is adapted to handle all kinds of tablethe sterilizing rays, and is adapted to receive ware including plates or dishes in a variety of dishes or articles of different sizes and shapes. sizes, and articles of such nature that they can- Another object oi the invention is the provision not be economically discarded after being used 30 oi a combined dish washing and sterilizing mabut once. chine adapted to wash dishes or like articles, and The washing machine oi Fig. 1 may be oi any then subject the washed dishes to a sterilizing suitable type and is shown conventionally as comradiation of such character that bacterial growth prising a housing ID in which a conveyor I2 is is destroyed and the drying of the articles is ac mounted ior the movement of articles through a celerated. the machine and within the range of suitable Other objects and advantages oi. the invention washing jets as indicated by the sprays i3 and it. will be apparent from the following description, In the illustrated arrangement, the conveyor t2 th accompanying drawings, and the appended is an endless chain structure which passes from 40 clamm the washing machine housing Iii directly into a 40 In the drawings. which m referred housing It within which the articles on the conembodlments or the invention: veyor are exposed to sterilizing radiation.

The housing I6 of the sterilizer is arranged so ha i s rilizer con sfjru ct d ir i e fi cfe l ge wi t fi tliis ins' ntion that the articles to be sterilized may pass i through it upon the conveyor, and while in t e 45 Zigz g; fif g zs gg being P away for clear machine will be totally exposed to an action which renders them sterile. As shown, the conveyor 2 is sectional View taken on the mm 2-2 i2 is supported for transit through the sterilizer 15 housing upon parallel tracks [I which are sup- Fla31sadeta111np1anofaporflonoithewnported from the side walls 20 and 2| of the 50 veyo sterilizer upon suitable brackets 22. The steriliz- Fis. 4 is a sectional view taken on the l ing radiation may be generated from any suitable 4-4 of Fig. 1; source and is shown as being provided by electric Fig. 5 is a sectional view taken on the line arcs 24 which generate radiations oi ultra-violet 8-5 oi Fig. 4; light. The area may be supported in any suitable 55 tracks I8.

manner and are shown positioned adjacent an opening 26 in the side 2| of the sterilizer. The opening 26 and arcs 25 arecovered by a door structure 25 which is preferably provided of such shape and material that it will serve as a reflector, and is shown as being attached to the sterilizer side 2| by means of a hinge 2'! and latch 28 whereby it may be readily swung open to provide access to the arcs. The relative positioning of the opening 25, the door 25, and the arcs 24 is such that sterilizing radiation from the arcs may pass directly into the housing and onto articles conveyed therethrough such, for example, as the tumbler shown. The shape and character of the arc door 25 is such that radiation in the direction away from the conveyor is reflected toward the housing interior. A second reflector Si is provided within the sterilizer and is positioned so that radiation from the arcs and from the reflector of the door 25 which strikes this reflector 3| is re-directed toward the conveyor to provide sterilizing action on portions of the articles which are not reached by direct radiation.

The sterilizer is constructed so that when ultra-violet light or some other radiation which may be harmful to the attendant is used the radiation is restricted to the confines of the housing. This may be accomplished by the use of a material for the housing walls which is impervious to the passage of the sterilizing rays, or by applying a surface coating of such material to the walls of the housing. Lead, for example, is a material which is known to possess the property of serving as a barrier to the sterilizing rays and this may be readily applied as a surface coating. As shown, the open ends 33, through which the conveyor i2 enters and leaves the sterilizer, are effectively closed to the passage of sterilizing radiation by the provision of spaced curtains 34 at both ends of the machine. These curtains, like the housing walls, are preferably formed of metal which is impervious to the passage of the sterilizing rays, and are fabricated to provide a flexible screen. The curtains are shown as being suspended from cross rods 35 which are supported from the side walls 20 and 2| of the sterilizer housing. The curtains, being of flexible material, are displaced as the articles pass beneath them when moving into and out of the machine and, by being spaced as shown, one or another of the curtains is always in such position as to provide an effective barrier to the passage of rays through the openings 33. An inspection window may be provided in the sterilizer such as that shown at 31; tthis being constructed of a suitableglass having the property of filtering out the harmful rays.

The conveyor |2,-as mentioned, is in the form of an endless chain, and is provided with suitable driving means such as the motor which drives a gear reduction 4| connected by a chain 42 to. rotate a shaft 43 that carries a drive wheel 44 of the conveyor. The shaft 43 is supported from the sterilizer upon suitable brackets 46 and the drive wheel 44 is shown of sufllcient diameter to provide a suitable spacing between the feeding" and the return runs of the chain I2. The conveyor l2 comprises link assemblies which are connected by and are supported upon spaced wheel structures; each wheel structure comprising an axle shaft 48 that carries a pair of flanged wheels 49 so spaced on the axle as to engage the As shown, theaxle shafts 48 are of such length that end portions 50 extend beyond the wheels 49 for attachment of the link assemaoeaeoa of the axles held by the member 52. The rigidly attached member is non-circular in section and is of such shape that when the side members 52 and 53 are joined by it they may not turn with respect to one another, consequently the axles 4B, which are rotatably received in the side plates,

will be maintained parallel. The link assemblies are held together and to the axles by the use of cotters 56. As shown, the links are assembled to the axles so that the link plates 53 lie adjacent the wheels and are positioned alternately at opposite ends of adjacent axles. The side plates 52 with the attached rods 55 are then placed upon the axle ends between the links 53 and so that the attached rod 55 extends across and engages the opposite plate 53; the assembly being completed by attachment of the cotters 56.

The conveyor is arranged so that articles supported thereon will be moved relatively to the conveyor as it moves, ,and consequently will be turned so as to present the entire surface of the article for exposure to the action of the sterilizing rays as the articles pass within effective range of this radiation. An arrangement for supporting dishes or plates for transit through the sterilizer is illustrated in Figs. 4 and 5. Grooved rolls 50 are shown adjustably positioned on the axles 48 of adjacent wheel structures to receive the rim of a plate 58 which is caused to stand in engagement with the rolls 60 by means of a support 83 which is attached to the intermediate 'member 55. A plate support 63 comprises a sleeve which is slidably received on the member 55 and is provided with means such as the set screw 56 by which the sleeve may be held to the member 55 in' desired position. A stud. 6"! projects upwardly from "the sleeve portion 64 and, as the member 55 is of non-circular shape, this member is maintained in an upright position. A telescoping member 68 is received on the stud 61 and is provided with a laterally extending flnger 69 which is adapted to engage a plate for its support upon the rolls 60. The member 68, like the member 64, is adjustable and may be held in adjusted position by means of a set screw 10. The universal adjustment provided in the support 63 permits the positioning of this device to be readily altered so that plates of varying size may be supported in any desired position. The support is preferably adjusted so that the contacting finger 89 does not contact with the center of rotation of the article supported, but instead is so placed that it contacts with the moving plate at a point away from the center'of rotation so that it does not hinder complete coverage by the rays.

Articles such as tumblers are readily supported for transit through the machine on a support as shown in Fig. 6. A sleeve 12 slidably mounted on a rod 55 is provided with rolls I3 which are adjustable to cause a tumbler to rotate in contact with the faces of the conveyor wheels 49 while guided by the flanges15 of these wheels. The sleeve 12, like the sleeve 64, is adjustably mounted and may be held in desired position by means of a set screw I6. Members 18 of similar shape, and which carry the rolls 18, are held in spaced parallel position in the bracket 12. The members 18 comprise threaded stem portions 19 which are shown asbeing slidably received within the sleeve 12. The threaded portions 19 are provided with adjusting nuts 00 which lie in contact with the upper face of the member 12 so that upon rotation of these the members 18 may be moved vertically to provide adjustment for proper handling of articles of varying size. To maintain the members 18 in proper operating position they are each provided with a slot II which is engaged by a set screw 82 of the member II to prevent the member [8 from turning. If desired the set screws .2 may be drawn tightly so as to hold the members 18 rigidly to the sleeve I2. justment provided for this supporting device permits it to be moved lengthwise of the rod 55 as well as to be adjusted vertically for support of the articles. With such an arrangement the rolls It may be adjusted to engage the bottom edge of a tumbler and hold this article inclined so that the opposite end of the tumbler will be retained upon the wheels 49 and against the wheel flanges l5.

By supporting the articles during transit through the machine upon parts of the conveyor which rotate as the conveyor moves, the articles are rotated relatively to the conveyor and are constantly turned so as to provide for effective exposure of the surfaces of the articles to treatment.

The supporting devices described permit the articles to be carried through the machine in such a manner that they will readily drain and, when subjected'to heat within the sterilizer, will be quickly dried. The supporting parts which come in contact with the articles, such for example as the finger 69 and rolls 60 and 13, are preferably formed of Bakelite or some other material which is not liable to chip the dishes when placing them on the carriers. The use of such material tends to eliminate noise in operation as well as prevents wear and marking of the articles transported.

The sterilizing aadiation may be generated from any suitable source and, as mentioned, in the illustrated embodiment of the invention electric arcs are provided which radiate ultra-violet light for sterilization of the articles. When more than one arc is used they are preferably spaced in such a way that the light with the aid of refiectors 25 and 3| is distributed uniformly throughout the path of travel of the articles when within effective range of the radiation.

The circuits which supply electrical energy to the arcs 24 and to the driving motor 40 of the conveyor are connected so that the machine is automatically rendered inoperative upon encountering abnormal conditions during use. As shown, leads 85 and 86, which are connected to a source of current supply, terminate at a switch 81 from which leads 88 and 89 extend. The lead 88 which terminates at the arc 24 has incorporated in it an automatic switch 90 that is actuated uponopening of the arc housing 25 so that this circuit may be energized only when the are housing is in a closed position. This restricts the radiation to the confines of the housing. The lead 89 terminates in a junction point 92; one branch continuing through a solenoid coil-83 and terminating at the opposite side of the are from the-lead The universal ad- 80. The other branch from the junction point 92 extends to one contact 95 of a switch structure; the other contact 88 of this structure being connected to a lead wire 91 which extends to a terminal 9| on the motor Ill. The other terminal I" of the motor is connected by a wire IM to the lead II. The circuit across the contacts 95 and 96 is completed by a normally open switch arm "II which is supported from the core ll) of the solenoid 08 so that the motor circuit may be energized only when the arc circuit is complete and is energized.

Normal operation of the machine is provided by closure of the switch 81 to energize the arc circuit for radiation of the ultra-violet light, and to energize the solenoid for closure of the switch arm I03 to energize the motor 40 and provide movement in the conveyor. Such an arrangement of parts causes the motor to be controlled by the arc circuit and also, by provision of switch 80, permits current to flow to the arc circuit only when the radiation from the arc will be limited to the confines of the housing as the automatically operated switch 90 in the arc housing 25 renders the arc circuit inoperative whenever this switch is open. Incorporation of this switch limits the use of the arc to such times as the arc housing is closed, consequently it is impossible for the sterilizing rays to radiate beyond the confines of the housing where they might be harmful to the attendant of the machine. Whenever the arc circuit opens, either through opening of the switch 90 or failure of the are 24, the motor circuit is also opened by action of the solenoid so that articles are prevented from being moved through the machine except when subjected to the sterilizing action of the arcs.

To provide for actuation of the motor and operation of the conveyor independently of the arc circuit a separate current supply is provided so that the motor alone can be energized. This circuit comprises leads I05 and I06 which are attached respectively to the main leads 85 and 8B and terminate at a manually operable switch llli from which leads I08 and I09 connect respectively to the motor terminals Hill and 98. The switch Illl is preferably housed under lock and key so that the machine attendant or any other unauthorized person may not tamper with it, and it will be accessible only to a proper person who may desire to inspect or adjust the machine.

The germicidal action of the sterilizing radiation may be accelerated by treating the articles to be sterilized with a suitable activating agent.

The activating agent may be readily applied to hydrid may be used as activating agents.

When a sterilizer is used in combination with a dish washing machine the application of an activating agent becomes. a very simple matter as it may be applied in solution from one of the washing or rinsing jets, or may be applied from an independent jet following the washing operation. Fig. 8 illustrates a construction incorporating a dish washing apparatus with a sterilizer in which means are provided for applying an activating solution to the articles prior to their exposure to the sterilizing radiation. As shown, the structure comprises a. housing 5% having a? conveyor :22 which is adapted to support articles during transit through the machine. The conveyor, like that illustrated in Fig. l, is

in the form of an endless chain having suitable driving means I23 which actuates a drive wheel lit for article advancing movement of the chain. The conveyor chain comprises a series of rollers G25 interconnected by links I25 with which are associated suitable means for supporting articles such as the dishes i28 shown in the figure.

During transit through the machine the dishes are first subjected to the action of sprays of a washing solution which issues from Jets I30 carried on a rotary wash arm i3l supported at m2 from the housing I20, and supplied with washing solution through the pipe I33. After passing from the washing zone the articles are'subjected to sprays of rinse waterfrom the Jet E which is supplied from a suitable source by means of the pipe I38. Further advance of the articles brings them within the range of spray jets I38Qand l39 from which sprays of an activating agent are directed toward the articles. In the illustrated embodiment of the invention a recirculating system is provided whereby the solution containing the activating agent may be collected for use again. As shown, a collecting basin or reservoir I40 is provided beneath the sprays I38 and I33 to collect the fluid discharged therefrom. A motor driven pump unit M2 is provided having a suction connection I with the reservoir I40, and discharge piping I46 connecting from the pump to the jets I38 and i39. Operation of the pumping unit causes a continuous circulation of the activating agent across the path of travel of the articles which are'to be sterilized. Contamination of the several sprays used in the washing and rinsing operations is prevented by provision of suitable flexible curtains MI which serve to divide the structure into compartments whereby the flow from each set of sprays is directed to drain within certain definite areas of the machine. Further separation is provided by the provision of bafiies such as that shown at 58 which directs the diflerent washing and rinsing solutions into proper reservoirs such as that shown at 0.

The activating agent may be introduced in solution with the washing fluid if it should be desired to have the sterilizing operation follow directly after the washing operation, or the activating agent may be introduced with the rinsing water prior to subjection of the articles it may be used in a very dilute solution; as little as one part in one million having been found to aoeasoa be a suflicient concentration to produce the desired results although even weaker solutions of this substance may be used satisfactorily. The use of an activating agent such as eosln serves to accelerate the germicidal action of the sterilizing radiation to substantially ten times the bacteria killing power of the radiation when used without an activating treatment. This increase in the germicidal action provides for increased efilciency in several different ways in that it serves to reduce the energy required to provide a satisfactory sterilizing radiation, or to increase the germicidal effect a substantial amount, or to materially increase the sterilizing capacity of the machine.

The germicidal efiect of a sterilizing radiation in the form of ultra-violet light is also accelerated in the presence of heat. In a sterilizing radiation generator of the character described about 6/11 of the energy consumed is converted into heat. The temperature of the arcs is in the neighborhood 01 3000 degrees, and in an arc generator consuming 1600 watts the temperature within the enclosed sterilizer becomes quite high so that the germicidal eiiect produced by direct radiation is accelerated in the presence of the high temperature within the sterilizer.

y moving the articles across the path of the sterilizing radiation at a distance of 4 to 5 inches from the source of radiation theheat generated at the source of the sterilizing radiation has an opportunity to become sufllciently dissipated to eliminate the possibility of damaging the articles by cracking them due to sudden temperature change, while providing an effective germicidal action by exposure well within the effective range of this radiation.

While the method herein described, and the forms of apparatus for carrying this method into effect, constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to this precise method and forms of apparatus,and that changes may be made in either without departing from the scope of the invention which is defined in the appended claims.

What is claimed is: y

1. The method of cleaning and sterilizing dishes and the like which comprises subjecting the dishes to the action of washing sprays, and then concomitantly subjecting the washed dishes to a drying action and to a sterilizing light radiation within the efiective range of such sterilizing light radiation.

'2. The method of sterilizing dishes and the like which comprises treating the dishes with an activating agent which enhances the germicidal action of a sterilizing radiation, and then subjecting the treated dishes in the presence of the activating agent 'to the germicidal action of a sterilizing radiation.

3. The method of drying and sterilizing wet dishes and the like which comprisesconcoinitantly heating the dishes to dry them and subjecting the dishes to a germicidal action. by exposure to a sterilizing radiation.

4. In a device of the character described for sterilizing dishes and the like, a housing, means for generating a sterilizing radiation within the housing, means for conveying dishes through the housing and within the effective range of the sterilizing radiation, and means automatically rendering the conveying means inoperative upon interruption of the generation of the sterilizing radiation.

5. In a sterilizer adapted to direct a sterilizing radiation upon articles, an electrically operated sterilizing light ray generator; means for moving the articles to be sterilized within the eflective range of the rays, a motor for driving said means,

control means for said motor and radiation generator for automatically eflecting coordinated control of the generation of the sterilizing light rays and or the energization and de-energization of the motor.

6. In a sterilizer adapted to direct a sterilizing radiation upon articles, an electrically operated sterilizing light ray generator, means for moving the articles to be sterilized within the eifective range of the rays, a motor for driving said means, control means for said motor and radiation generator for automatically eii'ecting coordinated control of the generation of thesterilizing light rays and oi the energization andde-energization of the motor, and means operable independently 01 said control means for causing operation of the motor without energizing the sterilizing ray generator.

7. In a device of the character described for sterilizing dishes and the like, a housing, a sterilizing ray generator positioned within the conlines of said housing, a door in said housing, and control means for such generation actuated in coordinated relation with the positioning oi said door.

8. The method of washing and sterilizing dishes and the like, which comprises applying to the dishes a spray of washing liquid containing an activating agent which enhances the germicidal eifect of a sterilizing radiation, and then, sub- Jecting the washed dishes in the presence of activating agent retained thereon to the action of a sterilizing radiation.

9. In a device 01' the character described for sterilizing dishes and the like, a housing. means for supporting the dishes within the housing. a sterilizing ray generator positioned within said housing, an electric circuit for said ray generator. 1 door in said housing providing an opening for inspection of said ray generator, and means for automatically breaking the electric circuit of said ray generator when said door is opened.

HERBERT L. J OHNBTON. 

